An adaptive annulus isolation tool

Abstract

This invention relates to an adaptive annular packer tool. The central tube is cylindrical with four inlet holes evenly distributed circumferentially near the left end, and a triangular thread on the outer side of the center. The sleeve is annular, with six pin holes evenly distributed axially on the right end. The left retaining ring is cylindrical with a pin groove on the outer side of the center, a triangular thread on the inner side of the center, and a 45° conical surface on the inner right end. The rubber sleeve is annular, with a larger outer diameter at the center than at the sides, and 45° conical surfaces at both ends. Each right retaining ring is fan-shaped; ten right retaining rings evenly distributed axially form an annulus, with a tubular structure on the right end containing a spring. The spring is located inside the tubular structure on the right end of the right retaining ring and is compressed during installation. Ten holes are evenly distributed circumferentially on the left end of the end ring. This adaptive annular packer tool can achieve permanent packing of irregular annular shapes.

Description

Technical Field

[0001] This invention relates to the field of oil well completion, and in particular to an adaptive annular packer tool. Background Technology

[0002] Annular isolation is a common procedure in oil well completion. Its main function is to isolate oil and gas layers with different pressures (or temperatures) or between oil and gas layers and non-producing layers (such as water layers), in order to prevent interference between fluids or pressure systems of different properties in different layers, thereby enabling the separate exploitation of producing layers.

[0003] There are two main methods to achieve annular isolation: one is to use cementing, circulating cement slurry into the annulus, and sealing the segment after the cement solidifies; the other is to use conventional packing tools, running the packing tool into the segment to be isolated and using compression or expansion sleeves to achieve isolation. Faced with increasingly challenging exploration and development, achieving isolation in irregular wellbore segments has become a major challenge. Neither of the above two methods is adequate for annular isolation in irregular wellbore sections. This is because the cement slurry, during its flow, is located in the lower part of the wellbore, resulting in incomplete isolation of the upper part. This is particularly pronounced in deviated and horizontal wells. Conventional packing tools, after setting, have a circular cross-section, which provides insufficient contact stress for irregular wellbore structures, often leading to seal failure.

[0004] Therefore, to improve the level of annular sealing technology, it is necessary to develop tools or technologies that can automatically adapt to the shape of the wellbore. Summary of the Invention

[0005] To achieve continuous sealing of the annulus packer in irregular wellbore sections, this invention provides an adaptive annulus packer.

[0006] This adaptive annular packer tool includes: a left connector, a central tube, pins, a sleeve, a left retaining ring, a rubber sleeve, a right retaining ring, a spring, an end ring, and a right connector. The left connector is a ring-shaped structure with threads on the inner side of the left end and threads on both the inner and outer sides of the right end. The central tube is a cylindrical structure with threads on the outer sides of both ends, connecting to the left and right connectors respectively. Four inlet holes are evenly distributed circumferentially near the end on the left side, and a triangular thread on the outer side of the middle section. The sleeve is a ring-shaped structure with threads on the inner side of the left end connecting to the left connector, and six pin holes evenly distributed along the axis on the right end, connecting to the left retaining ring via pins. The left retaining ring is a cylindrical structure with two sealing grooves on both the inner and outer sides of the left end, a pin groove on the outer side of the middle section, and triangular threads on the inner side of the middle section opposite in direction to the threads on the outer side of the central tube. The inner side of the right end has a 45° conical surface, and the right end is a thin cylindrical shape to protect the rubber sleeve. The rubber tube has a circular ring structure, with the outer diameter at the center larger than the outer diameters at both sides. Both ends have 45° conical surfaces that fit with the left and right retaining rings. Each right retaining ring has a fan-shaped structure; ten right retaining rings evenly distributed along the axis form a ring. The left end of the right retaining ring is cylindrical to protect the rubber tube, with a conical surface on its inner side. The right end is a cylindrical structure that inserts into the hole at the left end of the end ring, containing a spring. The spring is located inside the cylindrical tube at the right end of the right retaining ring and is in a compressed state during installation, with its left end in contact with the right retaining ring and its right end in contact with the end ring. Ten holes are evenly distributed along the circumference of the left end of the end ring. Each hole houses the cylindrical tube at the right end of the right retaining ring and the spring. The right end has threads connecting to the right connector. The left end of the right connector has threads both inside and outside, connecting to the end ring and the central tube respectively. The left end has two sealing grooves on its inner side, and the right end has threads on its outer side.

[0007] This adaptive annular packer seals irregular annulus spaces under the combined action of surface pressure and springs. The adaptive annular packer is installed at a specific location in the completion string according to the well design. After being lowered into the designed position in the well, the internal pressure of the tool is increased. Well fluid flows through the inlet port on the left side of the central tube, pushing the left retaining ring. When the pressure increases to the tool's starting pressure, the pin is sheared, the left retaining ring squeezes the rubber sleeve, and the sleeve gradually bulges until its outer surface contacts the well wall, completing the initial setting process. After the rubber sleeve is set, the triangular threads on the inner side of the left retaining ring are opposite in direction to the triangular threads on the outer side of the central tube, forming a reliable lock. The springs are compressed by the right retaining ring and end rings. When the wellbore is irregularly shaped, the contact stress between the rubber sleeve and the well wall is not uniform in the circumferential direction. Ten springs evenly distributed circumferentially extend a certain distance according to the contact stress of the rubber sleeve, releasing pressure and pushing each right end ring to move a certain distance to the left, creating secondary compression deformation of the rubber sleeve to varying degrees in the circumferential direction. The adaptive annular packer tool automatically adjusts the contact stress between the rubber sleeve and the wellbore by using different thrusts from each spring on the right end ring.

[0008] Compared with existing technologies, the advantages of the adaptive annular packer tool of the present invention are as follows: (1) The tool setting process is divided into two stages. The first stage is achieved by the left retaining ring pushing the rubber tube, and the second stage is achieved by the spring pushing the right retaining ring. The two stages ensure the long-term setting of the annular packer tool; (2) The 10 springs evenly distributed along the circumference can automatically release pressure and squeeze the rubber tube again according to the contact stress between the corresponding part of the rubber tube and the well wall, so as to achieve adaptive contact between the rubber tube and the well wall in the circumference direction; (3) There is a pin between the sleeve and the left retaining ring, which can prevent the tool from being set prematurely during the lowering process; (4) There are triangular threads on the inner side of the left retaining ring and the outer side of the central tube. When the tool is set, the two threads can be interlocked to prevent the seal from failing. Attached Figure Description

[0009] The invention will now be described from the perspective of embodiments and with reference to the accompanying drawings.

[0010] Figure 1 This is a schematic diagram of the structure of an adaptive annular sealing tool and method according to the present invention. Detailed Implementation

[0011] The invention will now be further described with reference to the accompanying drawings.

[0012] Figure 1 This is a schematic diagram of the structure of an adaptive annular sealing tool and method according to the present invention.

[0013] The adaptive annular sealing tool includes: left connector 1, center tube 2, pin 3, sleeve 4, left retaining ring 5, rubber sleeve 6, right retaining ring 7, spring 8, end ring 9, and right connector 10.

[0014] The adaptive annular packer tool is installed at a specific position in the completion string according to the well design. After being lowered into the designed position in the well, the internal pressure of the tool is increased. The fluid in the well passes through the inlet port on the left side of the central tube 2, pushing the left retaining ring 5. When the pressure increases to the tool's starting pressure, the pin 3 is sheared, and the left retaining ring 5 squeezes the rubber sleeve 6. The rubber sleeve 6 gradually bulges until its outer surface contacts the well wall, completing the initial setting process. After the rubber sleeve 6 is set, the triangular threads on the inner side of the left retaining ring 5 are opposite in direction to the triangular threads on the outer side of the central tube 2, forming a reliable lock. The spring 8 is compressed by the right retaining ring 7 and the end ring 9. When the wellbore is irregularly shaped, the contact stress between the rubber sleeve 6 and the well wall in the circumferential direction is not the same. The 10 springs 8, evenly distributed along the circumference, extend a certain distance according to the contact stress of the rubber sleeve 6 to release the pressure, pushing each right retaining ring 7 to move a certain distance to the left, forming a secondary compression deformation of the rubber sleeve 6 in the circumferential direction. The adaptive annular packer tool automatically adjusts the contact stress between the rubber sleeve 6 and the well wall by using different thrusts from each spring 8 on the right retaining ring 7.

[0015] The aforementioned adaptive annular sealing tool can achieve both primary and secondary setting, ensuring a durable and reliable annular sealing effect. Furthermore, the circumferentially distributed spring 8 can adaptively adjust its extension and contraction based on the magnitude of local stress during setting, guaranteeing the adaptive sealing effect of the annulus.

Claims

1. An adaptive annular sealing tool, comprising a left connector (1), a central tube (2), and a right connector (10) connected in sequence, wherein a rubber sleeve (6) is fitted around the central tube (2), and a sleeve (4), a left retaining ring (5), a rubber sleeve (6), a right retaining ring (7), and an end ring (9) are fitted around the central tube (2) from left to right in sequence; a spring (8) is provided between the right retaining ring (7) and the end ring (9); a plurality of circular tubes are provided on the left end face of the end ring (9), and the springs (8) are installed inside the circular tubes, wherein the right retaining ring (7) compresses the springs (8) inside the circular tubes; characterized in that, Each right retaining ring (7) has a fan-shaped structure. Ten right retaining rings (7) evenly distributed along the axis form a ring. The right end is a cylindrical structure that is inserted into the hole at the left end of the end ring (9). There is a spring (8) inside the cylindrical structure. The spring (8) is located inside the cylindrical tube at the right end of the right retaining ring (7). It is in a compressed state during installation. The left end is in contact with the right retaining ring (7), and the right end is in contact with the end ring (9). Among them, the 10 springs (8) evenly distributed along the circumference extend a certain distance according to the contact stress of the rubber cylinder (6) to release pressure, push each right retaining ring (7) to move a certain distance to the left, forming a secondary compression deformation of the rubber cylinder (6) to different degrees in the circumference, so as to realize the automatic adjustment of the contact stress between the rubber cylinder (6) and the well wall.

2. The adaptive annular sealing tool according to claim 1, characterized in that, The central tube has a cylindrical structure with four liquid inlet holes evenly distributed along the circumference near the end on the left side, and a triangular thread on the outer side of the middle.

3. The adaptive annular sealing tool according to claim 1, characterized in that, The sleeve (4) has a circular structure with 6 pin holes evenly distributed along the axis on the right end.

4. The adaptive annular sealing tool according to claim 1, characterized in that, The left retaining ring (5) is a cylindrical structure with two sealing grooves on the inner and outer sides of the left end, a pin groove on the outer side of the middle part, a triangular thread on the inner side of the middle part that is opposite to the thread direction on the outer side of the central tube (2), and a conical surface at a 45° angle on the inner side of the right end.

5. The adaptive annular sealing tool according to claim 1, characterized in that, The rubber tube (6) has a circular ring structure with a larger outer diameter in the middle than on both sides. The left and right ends have conical surfaces at a 45° angle that fit with the left retaining ring (5) and the right retaining ring (7).

6. The adaptive annular sealing tool according to claim 1, characterized in that, The left side of the sleeve (4) and the right side of the end ring (9) are limited by steps set on the left connector (1) and the right connector (10); the left end of the end ring (9) has 10 holes evenly distributed along the circumferential direction, and each hole is equipped with a right end tube of the right stop ring (7) and a spring (8).

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